[U-Boot-Users] PCI cards known to work on the LITE5200

[olivier at singla.us]

Hi Mark,

> Hello,
>
>> I am currently using a LITE5200. There is a known (annoying)
>> PCI issue with the MPC5200, and therdfore most of the PCI
>> cards I have tried on the LITE5200 were not recognized. For
>> several of them, u-boot even crashed (bus error). I was
>> wondering if somedy has tried with success common PCI
>> graphics cards and gigabit ethernet cards...
>
> Please note that this problem needs two partners to be seen. On the one
> hand, MPC5200 violates Tvalmin by having this about 1ns instead of at
> least 2 ns according to spec. On the other hand, a PCI card needs to be
> able to handle a Tvalmin of down to 0 ns when somebody reads from it. So
> if both sides behave badly the card is not recognized during Type-0
> configuration.
>
>> I have tried a suggested workaround, using an ICS574 to
>> adjust the MPC5200 PCI clock signal from the PCI bus, but
>> still no luck with the PCI cards I have tried (although it
>> should work with the PCI SM712 eval board).
>
> How did you adjust the clock using the clock buffer mentioned above?
> Overdoing it will also cause harm especially during writes. My suggestion
> is to measure the real Tvalmin and then adjust it that it just reaches 2
> ns.

Our Hardware engineer, John, has the following response:

Mark – thanks for the reply.  I did try to do what you suggested without
success but maybe I misunderstood something.  If I look at the PCI clock
and ADx signal, I see a Tval of about 0ns (ADx changing right along with
a rising PCI clock).  So I try to delay the PCI clock by approximately
27ns (33MHz PCI clock = 30ns clock period).  Since I think that this is
a free running clock, it should have the effect of ‘speeding up’ the PCI
 clock so that it gives a Tval of about 3ns.  I’ve tried other delay
values without success, but what I have described above is what I read
what I should try to do.  Am I missing something?  Thanks.